Disposable absorbent articles, in particular, disposable diapers, are designed to be worn by people experiencing incontinence, including infants and invalids. Such diapers are worn about the lower torso of the wearer and are intended to absorb and contain urine and other bodily discharges, thus preventing the soiling, wetting, or similar contamination of articles that may come into contact with a diaper during use (e.g., clothing, bedding, other people, etc.). Disposable diapers are available in the form of pull-on diapers, also referred to as training pants, having fixed sides. The fixed sides may be manufactured by joining side panels of the front portion of the diaper to side panels of the rear portion of the diaper. For joining purposes, the contacting surfaces of the side panels may be at least partially melted by directing heated fluid to areas of the contacting surfaces. Pressure may then be applied to the partially melted areas.
Consequently, during the process of joining substrates together, it would be beneficial to provide methods and apparatuses for more precisely directing the heated fluid and applying pressure to the partially melted areas of the substrates.